The immune response that results in the development of antibodies against the infused proteins may affect the clinical outcome of enzyme replacement therapy by the development of hypersensitivity, anaphylactoid, or febrile reactions, or may lead to the development of cytokine release and a generalized inflammatory response or immune complex formation. Furthermore, the mounted immune response may lead to inactivation or degradation of the recombinant enzyme or may change the pharmacokinetic and pharmacodynamic properties of the therapeutic protein.